How to return a function state in the event.get() function of pygame?

Question

I am currently working on a small project where I create a 2d game using pygame. But I am currently stuck with my collisions which are not working as I wished they do. I have a first function returning True or False when the character is in a boundary,

leaved = False
moving = False
player_collision = False

def Extracted_Data(x,y,x_speed,y_speed):
    global player_collision
    player_collision=False
    Player_Hitbox = pygame.draw.rect(gameDisplay,'black',((screen_width-png_width/4)/2 - x_speed,(screen_height-png_height/8)/2 - y_speed , tile_size , 3/4*tile_size),width=1)
    for row_index,row in enumerate(data):
        for col_index,val in enumerate(row):
            if val == 1025:
                Boundary = pygame.draw.rect(gameDisplay,'red',(x + col_index * tile_size, y + row_index * tile_size , tile_size , tile_size),width=1)
                if pygame.Rect.colliderect(Player_Hitbox,Boundary):
                    player_collision=True

                    return player_collision

Which I think is working properly as it prints 'Colliding' when it should. I then tried to detect if player_collision is True or False in my event.get() loop which is the part not doing the right thing.

while not leaved:
    print(player_collision)
    gameDisplay.fill('white')
    Background(x,y)
    Extracted_Data(x,y,x_speed,y_speed)
    Player(Img_Position)
    Foreground(x,y)
    Text()

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            leaved = True

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_q:
                Img_Position = Img_Positions.get("left")
                player_collision = Extracted_Data(x,y,player_speed,0)
                if player_collision == True:
                    print("left")
                    moving = False
                    x_speed = 0
                else:
                    moving = True
                    x_speed = player_speed
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_q or event.key == pygame.K_d:
                moving = False
                x_speed = 0
            elif event.key == pygame.K_z or event.key == pygame.K_s:
                moving = False
                y_speed = 0

    x += x_speed
    y += y_speed
    pygame.display.update()
    clock.tick(FPS)

pygame.quit()
quit()

Even if the collision is detected, the player can still move in the boundary. It will only be stuck if the key is released in the boundary. I think the problems come from the recovery of the player_collision state but I don't know how to fix this. I do not get any error message. Thank you in advance for any answer !

[Using global variables in a function](https://stackoverflow.com/questions/423379/using-global-variables-in-a-function) — Rabbid76, Jun 08 '22 at 18:16
Please trim your code to make it easier to find your problem. Follow these guidelines to create a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example). — Community, Jun 08 '22 at 21:05

The_spider · Accepted Answer · 2022-06-08T19:10:33.503

0

You should add a line global player_collision just after the line starting with def.

By default, every function has their own scope. This means that all variables defined and changed in this function are not defined or changed outside the function. When the function ends, all changes and defined variables are removed.

This can be changed using the global keyword. Declaring a variable global means that all its changes remain when the function ends, and thus can be used outside the function.

For more information, see an explanation about scopes.

edited Jun 08 '22 at 19:10

answered Jun 08 '22 at 18:10

The_spider

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I didn't know about this keyword does this means I don't need to ```return player_collision``` anymore? – Thomas Perr Jun 08 '22 at 19:03
I don't think you'll need to, but to be sure I need to see the way how you use this function. – The_spider Jun 08 '22 at 19:08
I updated the post with my newest version of the code where I added the global keyword. My print after the ```while not leaved``` is now working very well but the player can still go through boundaries as they are not detected in my ```if player_condition``` unless I press the key while in the collision – Thomas Perr Jun 08 '22 at 19:21

How to return a function state in the event.get() function of pygame?

1 Answers1